FreeBSD Project FreeBSD OS: Multiple Vulnerabilities

Risk Summary

When a challenge ACK is to be sent tcp_respond() constructs and sends the challenge ACK and consumes the mbuf that is passed in. When no challenge ACK should be sent the function returns and leaks the mbuf. If an attacker is either on path with an established TCP connection, or can themselves establish a TCP connection, to an affected FreeBSD machine, they can easily craft and send packets which meet the challenge ACK criteria and cause the FreeBSD host to leak an mbuf for each crafted packet in excess of the configured rate limit settings i.e. with default settings, crafted packets in excess of the first 5 sent within a 1s period will leak an mbuf. Technically, off-path attackers can also exploit this problem by guessing the IP addresses, TCP port numbers and in some cases the sequence numbers of established connections and spoofing packets towards a FreeBSD machine, but this is harder to do effectively. On a system exposing an NVMe/TCP target, a remote client can trigger a kernel panic by sending a CONNECT command for an I/O queue with a bogus or stale CNTLID. An attacker with network access to the NVMe/TCP target can trigger an unauthenticated Denial of Service condition on the affected machine. Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet. This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow. Notably, this does not require the client to authenticate itself first. As kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel. In userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets. We are not aware of any such applications in the FreeBSD base system. A regression in the way hashes were calculated caused rules containing the address range syntax (x.x.x.x - y.y.y.y) that only differ in the address range(s) involved to be silently dropped as duplicates. Only the first of such rules is actually loaded into pf. Ranges expressed using the address[/mask-bits] syntax were not affected. Some keywords representing actions taken on a packet-matching rule, such as 'log', 'return tll', or 'dnpipe', may suffer from the same issue. It is unlikely that users have such configurations, as these rules would always be redundant. Affected rules are silently ignored, which can lead to unexpected behaviour including over- and underblocking.

CVEs (4)

Affected Vendors

Affected Products (6)